Metal working



Sept. 24, 1963 c. 1 sPoRcK 3,104,565

METAL WORKING Filed May 22, 1959 1e sheets-sheen qfwfwmfm @L Sept. 24,1963 c.1 sPoRcK 3,104,565

METAL WORKING Filed May 22, 1959 16 Sheets-Sheet 2 Z lgVENTOR j BYMFMATTORNEYS C. L. SPORCK METAL WORKING Sept. 24, 1963 16 sheets-sheet :s

Filed May 22, 1959 ro--o--E @ZM if. MW# ATToRNl-:Y

Sept. 24, 1963 c. 1 sPoRcK METAL WORKING Filed May 22, 1959 16Sheets-Sheet 4 INVENTOR 92 BY /97 C: fwd i M 93 ATToRNEYs Sept. 24, 1963c. L. QsPoRcK METAL WORKING 16 Sheets-Sheet 5 Filed May 22, 1959 cefmadATTORNEYS Sept 24, 1963 c. L. sPoRcK 3,104,555

' METAL WORKING Filed May 22, 1959 16 Sheets-Sheet 6 INVENTOR ATTORNEYSC. L. SPORCK METAL WORKING Sept. 24, 1963 16 Sheets-Sheet 7 Filed May22, 1959 l lall:

ATTORNEYS Sept. 24, 1963 c. L. sPoRcK 3,104,565

METAL WORKING Filed May 22, 1959 16 Sheets-Sheet 8 'fr J5 X /l' /J l L:I I

:j y INVENTOR f /1 1 a @@Mffwf I l I BY /60/ Y); [/54 ATTORNEYS sept.24, 1963 Filed May 22, 1959 c. l.. sPoRcK 3,104,565

METAL WORKING 16 Sheets-Sheet 9 @am a@ l im 'JW/WW\\\\\\\\\ INVENTOR BYg g 1 j if ATTORNEYS Sept. 24, 1963 c. l.. sPoRcK A 3,104,555

METAL WORKING Filed May 22, 1959 16 Sheets-Sheet lO @M R Wwf/MM ATTORNEYS C. L. SPORCK sept. 24, 1963 METAL WORKING 16 Sheets-Sheet l1 FiledMay 22, 1959 Nvl-:NTOR

(lm f7/:amai BY v we# ATTORNEYS C. L. SPORCK METAL WORKING sept. 24,1963 16 Sheets-Sheet 12 Filed May 22, 1959 @ZM R?? BY M EY\S` Sept. 24,1963 c. 1 sPoRcK 3,104,565 v METAL WORKING Filed May 22, 1959 16Sheets-Sheet 13V 255 I ITVENTR Wywmw ATTORNEYS Sept. 24, 1963 c. L..sPoRcK 3,104,565

METAL woRKNG I lNvENTofR Sept. 24, 1963 C, L. sPoRcK 3,104,565

METAL WORKING 1N5 VENTO? BY HM M ATTORNEYS Sept. 24, 1963 C, SPORCK3,104,565

METAL WORKING Filed May 22, 1959 16 Sheets-Sheet 16 5,5/ 333535 J5@ j525 I, l 525' ATTORN EYS United States Patent O hio Filed May 22, 1959,Ser. No. 815,153 1S Claims. (Cl. Sil- 13) This invention relates to theart of metal working and in particular relates to methods and apparatusIfor forming hollow, generally cylindricallyshaped articles from sheetmetal blanks.

The invention is concerned with the making of elongated,cylindrically-shaped articles havin-g use in -a wide variety .ofindustrial and lmilitary applications, particularly where ihighstrength, light weight and precise dimensions are mandatory. Forexample, cylinders made in accordance with the invention may be used asstorage and control tanks, particularly in the chemical and doodprocessing industry. As to military use, the articles formed by themethods of the invention are ideally suited for components of rocketsand missiles such as fuel containers, skin parts, body structuralmembers and the like.

Components such as mentioned above for rockets and missiles may havedimensions in the order of the following: length: l(}"5'(l0"; thickness:.0110-111"; diameter: 20"-150". Such components are made by the familiarwrapping and |welding techniques Where a flat blank of rolled steel isformed into cylindrical shape, welded at the abutting edges and thenmachined to dimensions. These techniques have several disadvantages. Forexample, where the component is to be of substantial length, it isnecessary to Vform several like objects and then weld the adjacent ends.With such procedure it is very diicult to match diameters and tomaintain all of the parts coaxial so that the wall of the part is trulysymmetrical fwith respect to the axis. Complex and costly machiningoperations are required to maintain dimensions. Furthermore, the makingof large parts by these techniques ordinarily requires heat treatmentafter welding or machining -which often can lead to undesirabledistortions. Where high strength is desired, the thickness of thematerial must be disproportionately large which adds to the total weightand is Wholly undesirable in airborne devices. The outer skin of aballistic missile should be axially true as otherwise errors may arisein the desired trajectory, and for iiuel containers ttor rockets it isimperative that the inside dimensions be accurately controlled in orderthat the desired rate of burning will take place. Conventional wrappingand welding techniques do not lend themselves to the obtaining of thesedesired characteristics.

Besides the wrapping-'weldingemachining techniques mentioned above,cylinders and tubes have been made by the use of Iroller and spindlemethods lwherein a blank is supported on a spindle or a mandreland whilethe spindle and blank are rotating, one Vor more rollers engage theblank and with relative axial motion as between the roller and theblank, the Wall of the blank is reduced in thickness and elongated. Insome instances the blank has a closed end which is held in abuttingrelationship with the end of the spindle and the relative axial motionof the roller with respect to the blank is in a direction away from theclosed end, the reduced part of the yblank extruding along the spindleunder the -action of the roller so as to completely be formed on thespindle. In other instances the b-lank is supported on the spindle andmoved axially into the rollers or, conversely, the rollers are movedalong the blank (with one end of the blank being held fixed); in eithercase the relative axial motion of the roller with respect to the blankbeing such that the rworking forces are taken through the unworkedportion of the ,e ICC blank and the blank extrudes oli the end of thespindle. In still other instances the rollers are positively driven andalso oriented with respect to the spindle -so that the blank and spindleare pulled between the rollers rfc-r the reducing operation.

These methods have not been used heretofore ttor the yforming ofarticles of the kind in question because o-f several basic difficulties.

Many of the above-mentioned techniques contemplate that the blank be hotrolled. While hot rolling has many desirable advantages, it has thedistinct disadvantage of not producing strain hardening, and strainhardening is highly desirable in articles of the kind underconsideration because of the attendant improvements in strengthproperties.

The most significant disadvantage, however, lies in the failure of thesetechniques to provide for dimensional accuracy, particularly. withregard lto Wal-l thickness and inside diameter. The processes of thekind mentioned vabc-ve, at least insofar as -I am aware, contemplatethat the blank or the formed part expand -or open up after it leaves therollers. not provide that each axial increment of the nished part havethe rsame wall thickness and the same inside diameter as existed -at theltime of its reduction. r[This has the effect of making it impossible tohold close and uniform tolerances in diameter, wall thickness and axialconcentricity of the finished part. Furthermore, those processescontemplating the forming of the part completely on the spindle are .oflittle value for making articles of substantial length and diameterbecause of the practical ditliculties in making the required sizespindle.

With the above in mind then, the present invent-ion contemp-latesmethods and equipment for the forming of elongated, cylindrically-shapedarticles by way of roller `and spindle means but which are constructedand operated to eliminate the disadvantages of Ithe spindle-roller andthe wrapping and Welding techniques mentioned above and to providetfeature-s and advantages which are not present in and indeed areimpossible to obtain With such conventional techniques.

1t is one object of the invention to provide roller and spindleapparatus and methods Afor using the same lfor the production ofelongated, cylindrically-shaped articles having extremely highdimensional accuracy, both as Ito Wall thickness and inside and outsidediameter and axial concentricity.

Another object of the invention is to provide roller and spindleapparatus and methods of using the same for the production of elongated,generally cylindricallyshaped articles having extremely high strengthproperties yas compared to fthose of the initial starting blank andwhich have la very high degree 'of dimensional accuracy.

Another obje-ct of the invention is to provide roller and spindleapparatus and methods of using the same for the production of elongated,generally cylindricaliyshaped :articles having very Vhigh strengthproperties yet With a minimum of Weight and a high order of dimensionalaccuracy.

Another objeot of the invention is toprovide roller and spindleapparatus and methods of using the same for the production oi elongated,generally cylindrically-I In other words, present processes do curacy isprincipally a function of extrusion rate and that extrusion rate can bedesirably controlled by simultaneously reducing the discrete fractionalproportions of the blank. The principal `control factors foraccomplishing the foregoing are the number and extent of the fractionalreductions, the initial feed rate of the blank and the rotational speedof the blank, all of these being coordinated to produ-ce the desiredresult 4and the exact relationship of these factors depending upon thekind of material being worked.

In' one aspect the invention contemplates the forming of elongated,cylindrically-shaped articles by simultaneously reducing and extrudingdiscrete radial and axiallyspaced portions of the Wall of acylindrically-shaped blank and controlling the extrusion rates so thatthe extrusion rate of the finally-reduced portion is such that eachincrement of the formed article has the same inside diameter and Wallthickness as existed at the nal reduction.

In another aspect the invention contemplates the forming of acylindrically-shaped article by the elongation :and reduction of a blankby a roller cooperating with a spindle, the roller having a pluralitylof rolling sections serially spaced along the axis of the bla-nk witheach Working surface taking a fractional proportion of the total desiredreduction and with the blank feed rate, the rotation speed of the blankand the number and extent of the reductions being correlated to controlthe extrusion rate of the final reduction.

Another aspect of the invention contemplates the forming of axiallydimensioned, elongated, generally cylindrically-sliaped articles byspindle and roller means, the roller comprising a plurality of rollingsections simultaneously operating on the blank to reduce discreteportions iand move the same at different extrusion nates so that thelinal extrusion rate is such that the formed blank has a uniform wallthickness the same as the spacing between the spindle salnface and thefinal roller and a uniform inside diameter which is the same as theoutside diameter of the spindle.

In another aspect the invention contemplates the forming of accuratelydimensioned, elongated, cylin-dricallyshaped articles lby Way of aspindle and roller means having a plurality of rolling sections whichare serially spaced along the axis of the blank and each being locatedat a different radial distance from the axis of the blank so that eachrolling section effects a fractional proportion of the total reductionIrequired and operates simultaneously with the other sections anddetermining the linal extrusion rate by controlling the spindle speed,the blank feed rate and the number of reductions.

Plibe foregoing may be obtained by several different forms of equipmentbut it is essential that such equipment have certain basiccharacteristics. On'e of the most important of these is the constructionof the roller which provides for the simultaneous reduction andelongation of discrete portions tof the blank. Another is that 'theequipment must provide for the control of the blank `feed rate and theblank rotational speed and it is preferred that such control be variablein nature so that the equipment is adaptable for a Variety of differentmaterials and blanks of varying sizes.

According to the invention, the preferred form of roller has a pluralityo-f rolling sections, all of which are mounted on a common rotationalaxis and Vall have the same diameter and are held in closely abuttingrelationship with one another. Further, the invention contemplates thatthe roller be mounted so that it is tiltable with respect 4to therotational axis of the blank, the several rolling sections and thetilting being coordinated so that the roller may be positioned with eachof the rolling sections located at a different radial distance from therotational axis of the spindle and serially spaced along the axis of theblank. This per-mits each of the rolling sections to perform its work ondifferent tions of the blank.

In addition to the foregoing, the apparatus of the present inventionprovides a machine having a unique arrangement and construction of partsand a mode of operation all coordinated in a highly novel manner. Forexample, the invention contemplates that the roller means be non-movable(axially of the blank) and that the rotating spindle and blank, for theworking operation, be moved directly into the roller means. This is ofspecial advantage from the standpoint of simplifying the machineconstruction,

machine operation, savings in 4manufacturing and mainte-Y nance costs.This type of construction is not simply an engineering choice, so tospeak, as between whether to make the rollers move or to make thespindle move, because the lelection of a design incorporating spindlemovement involves the problem of how to effect spindle rotation While,at the `same time, providing for axial movenient. This problem becomescritical because itis highly desirable that the power for the movementbe hydraulic, in view of the large working forces involved. Rotatinghydraulic connections are highly undesirable in machines of the kind inyquestion because with the Vrather high rotational speeds involved andwith high unit pressure being applied for long periods of time (to eiectcomplete working of the blank), there is a very great danger of leakagewhich is highly undesirable from the standpoint of maintaining feedblank rate, the blank feed rate being impor- Y tant for maintaining thedesired extrusion irate.

The present .invention solves the foregoing problem by a uniquehydraulic piston and cylinder arnangement coupled d-irect-ly to therotating spindle and providing movenient thereof but with neither thepiston nor cylinder rotating.

The invention contemplates that the roller means comprise three rollerassemblies equally spaced about the rotational axis of the spindle andthat the spindle axis extend vertically so that during the Workingoperation the rotating spindleV and blank are moved upwardly .into thev.

rollers. This arrangement fhas several advantages, for eX- ample, inpermitting simplified construction for synchronizing the rollers, ie.,that corresponding parts of the rollers occupy the same radial distancesfrom the rotational axis of the blank and lie in the same transverseplanes.

Furthermore, by having the rollers each located at the vertex of atriangle, there is very little, if any, unbalanced radial thrust on thespindle. tendency of the spindle to buckle and is liighly desirable fromthe standpoint of maintaining dimensional accuracy.

Furthermore, `the spindle has a symmetrical construction so that thecenter of gravity is located along its rotational axis and, therefore,there is no radial thrust on the spindle or blank due to the forces ofgrav-ity. Also, the piston and cylinder means are arranged so that itsthrust for moving the spindle lies along the rotational axis of thespindle.

The apparatus of the invention contemplates that each of the rollerassemblies be controlled by tracer mechanism for the working operation.In the making of articles of the nature discussed, it is possible tolock each of the roller assemblies in a xed radial position. However,the use of tracer mechanism arranged as disclosed herein has distinctadvantages, particularly from the standpoint of controlling thedimensions of the articles being forme-d. Furthermore, in certaininstances it may be desirable to form an article having a tapered walland from this standpoint the tracer control is substantiallyadvantageous. For

tracer control the invention contemplates that each roller assembly bemounted to accommodate relative mot-ion as' therewith, the templet beingpreferably interconnected with peripheral sec- This, of course, avoidsanyV the piston and cylinder means so that, while being axially movable,it has no rotary motion.

While in the foregoing I have discussed in somewhat general terms thevarious advantages, features and objectives of the invention, it will beapparent as the description proceeds that the invention has other highlydesirable advantages and features.

The preferred manner of practicing the methods of the invention and thepreferred construction of a machine for practicing the same will beapparent from the following description and drawings wherein:

FIGURE l is a front elevational View illustrating the general assemblyof the machine;

FIGURE 2 isa plan view of FIGURE l;

FIGURE 3 is a plan section :taken on the line 3 3 of FIGURE 1;

FIGURE 4 is `a vertical section taken on the line 4-4 -of FIGURE 2 withcertain parts appearing in elevation;

FIGURE 5 is an enlarged, broken-out section of certain o-f the par-ts ofFIGURE 4;

FIGURE 6 is a vertical section taken `on the line 6 6 of FIGURE 4 withcertain parts omitted;

FIGURE 7 is an enlarged vertical section taken on the :line 7-7 ofFIGURE 2 and also on the line 7-7 of FIGURE 8;

FIGURE 8 a plan sect-ion taken on the line 8-8 of FIGURE 7;

FIGURE 9 is an enlarged plan section taken on the line 9 9 of FIGURE 10;

FIGURE l0 is a fragmentary cross section on the line lil-16 of FIGURE 9;l

FIGURE 1l is ya perspective view of a drive bushing used in the spindleassembly;

FIGURES 12, I3 and 14 are plan, side and end views respectively oftheroller assembly;

FIGURE is a plan section taken on the irregular line 15--15 of FIGURE 1vwith certain parts omitted;

FIGURE 16 is a vertical section taken on -the line 16-16 of FIGURE 15;

FIGURES 17, 18 and 19 are side, plan `and end views respectively -of thetracer valve .mounting structure;

FIGURE 20 is a diagrammatic view illustrating the hydraulic circuitsfo-r moving the roller assembly toward 'and away from the spindle axisfand for controlling the vertical motion of the spindle assembly;

FIGURE 2l is a diagrammatic view of the tracer valve;

FIGURE 22 is a schematic wiring diagram illustrating certain of theelectrical circuits used for operating the machine;

FIGURE 23 is a schematic wiring diagram illustrating the controls forcertain of the motors used in the machine; l

FIGURES 24, 25 and 26 are diagrammatic views illustrating the forming ofa yblank into an elongated cylindrically-shaped article;

FIGURE 27 is a fragmentary view illustrating certain of the operationstaking place in FIGURES 24--26 and FIGURES 28 and 29 are fragmentaryviews of alternative roller for-ms.

General Description As best seen in FIGURES l 'and 3, the machine M is'supported over a pit P by the door F and the columns C and C4 in thepit. While the Imachine could be mounted so that the lowermost partthereof was suspended just above the floor level, lthe pit arrangementis preferred in order to reduce the overall height of the machine.

The rbed of the machine comprises a main base 1 (see FIGURE 3) which hasconnected thereto the roller bases 2, 3 and 4. The roller bases arespaced approximately 120 apart from one another and respectively carrythe roller rests 5, 6 and 7 which support the roller assemblies 16,11fand 12. As best seen in FIGURE 3, the main base is apertured asindicated at 13 and within the aperture is supported the spindle orspindle assembly =14 (see FIG- URE 4) which is adapted to be rotated andmoved along its -axis of rotation which, in this instance, extendsvertically. The spindle assembly carries 'the lblank B. Connected witheach of the rollers 10i, 11 and 12. are tracer valves 15, 216 and 17which ycooperate with templets 2t), 21 and 22 for `controlling theposition of the rollers with respect tothe rotational .axis of the blankor spindle. The templets 20, 21 and 22 are mounted on templet supports23, '24 `and 25 which are all interconnected with the spindle to Ibemoved in a vertical direction therewith in a manner which will beexplained hereinafter.

The general manner in which the machine is used is explained following.The parts `are in the position as shown in FIGURES 1 and 6 and thespindle is rotated (causing rotation of the blank) and then movedvertically until such time that the rollers `engage with the blank. Withcontinued rotation and upward motion, the rollers work the blank,causing `a reduction in the wall thickness thereof `and the -blankextrudes upwardly and away from the spindle.

The Main Base As Ibest seen in FIGURES 3 and 4, the main base 1 is acompartmented structure comprised of Ivertical cross braces 26 .and`annularly-shaped horizontal braces 30, 31 and 32. As indicated inFIGURE 3, the base is supported at three point-s over the pit; vforexample, ione corner is supported by the column C, the other corner issupportedgby the column `C-l and the other corner is supported by thefloor as indicated at 29. 'The three annular braces 30, 31 and 32 formthe aperture 13 referred to heretofore. Within the aperture 13 is aspindle housing 33 which at the top rests on the brace 30 and on theside 'is supported laterally by the inwardly facing edges yof 'thebraces 30, 31 and 32. On the bott-om of the spindle housing is anannular-:shaped lower bearing housing 34 `and Aon the lower bearinghousing is a piston support 35 which, as indicated in FIGURE l, extendsdown -into the pit P. The cross sectional shape of the piston housingwill be seen from an inspe-ction of FIGURE l5. All of `the parts justdescribed are `all rigidly tied together by convention-al bolting meansto make a strong unied structure. Y

Roller Bases Each of the roller lbases 2, 3 and 4 are substantiallyidentical in structure and include vertically extending braces 40 asindicated in FIGURE 3 for the roller base 2. Each roller base is boltedto the main base.

The Roller Rests Each of the roller rests is identical in constructionand the description will be principally in connection with the rollerrest 5 as shown in FIGURES 7 'and 8. The roller rest has a main slide`411 by means of which the rest is mounted on top of the roller base 2.The roller rests are adapted to be adjustably moved toward and away fromthe rotational taxis A of Ithe spindle for purposes of setting up themachine for 'blanks of various diameters. For guiding this movement .andfor preventing any twisting movement of the roller rest during theworking operation, there are cooperating guide-ways in the Iform ofabutting shoulders on the main slide of the rest and the roller base;for example, see in FIGURE 6, the shoulders 46 and `47 on the main slideof r-oller rest 7 and the shoulders 4S and 49 on the roller base 4.Similar abutting shoulders r.for the roller ibase 2 and roller rest 5are indicated at Sti-Sil and S1-551 in `FIGURE 8.

The roller rest is adapted to I.be adjustably moved as describedfollowing. In FIGURE 7 a nut 52 is attached -to the bottom of the slide41 and this cooperates with a screw S3 mounted in the bracket 54 securedto the base Z. The screw is mounted so that it can be rotated `but notImoved axially. The screw may be manipulated by a wrench or the likeapplied to .the head 55. While it is not shown, the roller base 2 may beprovided with grooves on its top surface to receive hydraulic fluidtEorced into the grooves Iby appropriate pumping apparatus. This has theeiect of lubricating or lifting the rest away from the base so that thesame can be easily adjusted by means of the screw 55.

After the roller rest has been set to an adjusted position, it may belocked in adjusted position as described following. The shoulders 50 onthe base carry clamp plates 60 and 61 and the shoulders S1 of the basecarry clamp plates 62 and 63. These clamp plates are arranged so thatwhen the same are tightened down they engage the shoulders S and S1 onslide 41 and exert a large `force to hold the rest against movement andparticularly against backward tilting movement. To insure againstoutward; movement of the rest, the notches 64 and 65, cut in the plates61 and 63, cooperate with lock plates 66 and 70 fixed to the slide 41.

As best seen in FIGURE 2, the turnbuckle assemblies 71, 72 and 73 areconnected to and extend between the respective roller rests. Theturnbuckles rigidly tie the roller rests together and are 4forpreventing outward movement and tilting of the roller rests during aworking operation. 'Ihe turnb'uckles are adjustable to provide forradial adjustment of the roller rests as mentioned above.

'Ihe main slide 41 has a top cover 74 and these form a central aperturein the slide as indicated at 75 in FIG- URE 7. In vertical .crosssection the aperture is generally rectangular in shape as indicated forthe aperture 7S of the roller rest 7 shown in FIGURE 6. Within thisaperture is disposed the roller assembly.

The roller assembly 10 is slidably mounted on the roller rest toaccommodate relative motion between the assembly and the rest in adirection toward or away vfrom the rotational axis of the blank, thisrelative motion being controlled by the tracer valve 115 and thecooperating templet 20. The manner of mounting the roller assembly forsuch movement will next be explained.

The sides of the slide 41 Within the aperture are provided with a pairof guideways such as the ways for the roller rest 7 indicated at 76 and77 in FIGURE 6. Within the guideways of the slide 41 is disposed acradle slide 78 which in plan has a U-shaped cross section as indicatedin FIGURE 8. The relative motion as between the cradle slide and theIguideways is controlled by a piston and cylinder arrangement describedfollowing. 'Fhe slide 41 and .the ltop cover 74 (FIGURE 7) carry acylinder adapter 80 which mounts a cylinder body 81. On one end of thecylinder body there is a cylinder end cover 82 and on the other endthere is an kend cover S3. 'I'hese elements form the cylinder 84 withinwhich is disposed the piston 85. The piston 85 has a piston rodcomprising an enlarged section 86 and a reduced section 87 which isattached to the cradle slide 78. Also attached to the piston is an arm90 carrying an adjusting nut 91. The nut 91 is 'used in set-up purposes,particularly in determining the innermost position yof the rollerassembly .10.

The conduits 92 and *93 are ttor the supply of ll-uid for the cylinder84 so as to effect back and vforth movement of the piston or to permitback and dorth movement ot' the cylinder while the piston remains lixedas will be explained later.

Secured to the cradle slide 78 is a cradle 94 which is arcuate in shapeand has an arcuate guideway 95, the axis of the guideway lying in aplane which contains the rotational axis of the spindle. As seen inFIGURE 8, on either side of the -guideway are two slots 96 and 97.Mounted on the cradle is a swivel 100 which is also arcuate in shapeconforming to the shape of the Vcradle and has a portion '101 whichextends into the lguideway 95. The swivel carries a segmental part of aworm wheel 102 which cooperates with a worm 103 mounted on the cradle.The swivel also carries a plurality of T-bolts 104, the heads of whichcooperate -with the slots 96 and 97. When the TJbolts are tightened up,the swivel is held tightly on the cradle. When the lbolts are loosened,the worm 103 can be rotated by a wrench applied to the head 105 whichcauses the swivel to move along the cradle. The purposes of the swiveladjustment will be explained shortly.

The roller assembly 10 is mounted on the swivel and tarcuately movabletherewith. The roller assembly has a housing 106 which abufts the swiveland is xed thereto 'by means of bolts such as the bolts 107 for theroller :assembly 12 as shown in FIGURE 6. The roller assembly isarranged to be adjusted in a vertical direction by means of the nutwhich `is xed to the swivel and' a. sscrew 111 cooperating with threadsin the housing 106. The key 112 which is disposed in ways on the swiveland cradle guide this vert-ical adjustment. The vertical adjustment isfor placing corresponding parts of the roller assemblies in the samehorizontal planes.

Roller Assembly Each of the roller assemblies is identical inconstruction andthe explanation of this `will be principally in.connection with the roller assembly 10 which is shown in some detail inFIGURES 7, 12, 13 and 14.

'Ihe housing 106 of the roller assembly mounts a pair of -upper andlower bearing caps 115 and 116 which `are secured to the housing bymeans of the screws 1720 `(see FIGURE 12). Bearing caps 115 and 116support the covers 121 Iand 122. Within the assembly there is a rollershaft 123 being rotatably supported by means of the irrboard bearings124 and 125, and outboard bearings i126 and 127,V the bearings 124 and125 being disposed between the shaft and the caps, and the bearings 126,and 127 being disposed between the shaft and the covers.

The shaft has a shoulder 130 upon which bear the several :rollingsections-131, the sections being held rrn against the shoulder by thelock nut 132. This arrangement, to-

gether with the key 133, rigidly tie the'rolling sections` together forrotation.

In the present embodiment 'the rollin-g sections are all of lidenticalconstruction having the same diameter and identically'conigured Work-ingtips or working surfaces. As will be apparent from FIGURE 7, the rollingsections 131 are serially spaced along ythe rotational axis A of theblank B and the working ltips are spaced at different radial Vdistancesfrom this axis. As indicated heretofore,

ithe function of the rolling sections is to reduce fractional port-ionsof the blank and, from this standpoint, may be considered as independentrollers.

'Ihe roller assembly, the swivel and the cradle areY arranged so thatwhen `the swivel is arcuately adjusted, the

roller assembly pivots aboutthe point 135 of the work-V ing tip of thecenter rolling section. Since the roller assembly pivots about the point135, it will be seen that by ldifferent arcuate adjustments, thedifferent roller Working tips can be spaced dilerent distances from therotational axis A. For example, .in FIGURE 7 it will be seen that all ofthe live working tips occupy diierentV radial distances from this axis.If the roller assembly is then adjusted, say more counter-clockwise, thetop -rolling section will move closer to the axis while the bottomrolling section will move farther from the axis. The -center rollingsection, of course, does not move sinceV the roller is pivoting aboutits working tip. This arcuate adjustment of the roller assembly,together with the radial adjustment provided by the setting of nut 91provides for variation in the total reduction to be taken on a blank Vsothat the pivoting effects equal but opposite motion of correspondingsections on opposite sides of center.

The roller assembly is preferably mounted so that the rotational axis ofthe shatt 123 lies in a plane containing the rotational iaxis A of thespindle. Further, the` Where an even number of v

2. IN A MACHINE TOOL: A BED INCLUDING A ROLLER BASE; A SPINDLE FORSUPPORTING A BLANK TO BE WORKED; MEANS MOUNTING THE SPINDLE ON THE BEDFOR ROTATION ABOUT A GENERALLY VERTICAL AXIS AND FOR MOVEMENT ALONG ITSROTATIONAL AXIS; A ROLLER REST MOUNTED ON SAID BASE; TRACER TEMPLATESUPPORT MEANS AND A TEMPLATE MOVABLY MOUNTED ON SAID BASE; MECHANISMCONNECTING SAID SUPPORT MEANS AND SAID SPINDLE AND PROVIDING FOR THESUPPORT MEANS TO BE MOVABLE AXIALLY WITH THE SPINDLE BUT WITHOUTROTATION; A CRADLE HAVING A SLIDING CONNECTION WITH SAID ROLLER REST,THE CONNECTION PROVIDING FOR RELATIVE MOTION BETWEEN THE CRADLE AND THEROLLER REST IN A DIRECTION TOWARD AND AWAY FROM SAID AXIS AND THE CRADLEBEING FORMED WITH AN ARCUATE GUIDEWAY; A TRACER VALVE CONNECTED WITHSAID CRADLE AND COOPERATING WITH SAID TEMPLET;